The traditional centralized control of microgrids requires a centralized controller to control all DGs and other units in real time.The required communication network is complex and the system reliability is low,which can not meet the requirement of DG's plug-and-play.In recent years,the geographically decentralized and autonomous multi-agent system,which can cooperate with each other to realize the overall control objective,has received increasing attention and research,and has gradually been applied in power system.Therefore,the multi-intelligent system theory is utilized to design the distributed control structure for microgrids,and the consensus algorithm is applied to realize the distributed control of microgrids,which can provide a good theoretical basis and implementation method for the realization of distributed control of microgrids.And it is of important realistic significance and practical value for the promotion of renewable energy utilization and the construction and development of microgrids.Based on the multi-agent system theory and consensus algorithm,this paper studies the optimal energy management strategy and secondary coordination distributed control of microgrids.Firstly,this paper systematically introduces the fundamentals of graph theory and matrix theory,the multi-agent system theory,Lyapunov stability theory,and consensus algorithm andits application in power system.Graph theory and matrix theory are utilized for the design and performance analysis of multi-agent system communication network,which can describe the information exchange process among the agents.The multi-agent system theory is employed to design the system structure of distributed microgrid.Lyapunov stability theorm is used to analyse and judge the stability of the coordinated controller.Consensus algorithm provides a theoretical basis for the design and implementation of the coordination control strategy among each agent.These theories provide the basis for the energy management strategy and the coordinated coordination control strategy of distributed-control microgrids.Secondly,this paper studies the distributed energy management scheduling strategy based on MAS consensus theory,for the purpose of improving the economics of distributed-control microgrids.Taking the minimum cost of all DGs as the objective function and the microgrid power balance and DG output as the constraint condition,the optimal economic scheduling model of distributed-control microgrids is established.According to the multi-agent system framework and consensus algorithm,this paper presents a distributed energy management algorithm for microgrids,and gives the concrete implementation steps of distributed energy management scheduling strategy of microgrids.Through the simulation of a 4-node microgrid test system and IEEE-14 test system,the correctness and validity of the proposed scheduling strategy is verified.The scheduling strategy algorithm can exchange the information of each agent of microgrids through the communication network and adjust each DG output to realize the objective of the minimum cost of all DGs under the premise of satisfying the power constraint condition,and it has the advantage of satisfying the requirements of plug-and-play of DG and is suitable for time-varying load demand.Finally,this paper designs a distributed coordinated control strategy for voltage and frequency of microgrids,in order to realize the distributed consensus voltage and frequency control of isolated microgrids.Based on the analysis of the three control structures of microgrids,namely decentralized control,centralized control and distributed control,the distributed control structure of microgrids is designed based on multi-agent system,and the droop control system is employed as primary control of microgrids.The dynamic control model of inverter-based DG,including PQ controller,voltage and current controller,is established.The secondary distributed coordinated control of voltage and frequency is designed by using feedback linearization method and consensus algorithm and is applied in a 4-node microgrid system.The simulation results show that the distributed coordinated controller can realize the voltage and frequency consensus control for each DG,therefore verifying the correctness and validity of the proposed distributed coordinated control strategy. |